21259434 has 48 divisors (see below), whose sum is σ = 49871808. Its totient is φ = 6023808.

The previous prime is 21259417. The next prime is 21259439. The reversal of 21259434 is 43495212.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21259439) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 48882 + ... + 49314.

It is an arithmetic number, because the mean of its divisors is an integer number (1038996).

Almost surely, 2^21259434 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21259434, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24935904).

21259434 is an abundant number, since it is smaller than the sum of its proper divisors (28612374).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21259434 is a wasteful number, since it uses less digits than its factorization.

21259434 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 619 (or 612 counting only the distinct ones).

The product of its digits is 8640, while the sum is 30.

The square root of 21259434 is about 4610.7953760712. The cubic root of 21259434 is about 277.0238958997.

The spelling of 21259434 in words is "twenty-one million, two hundred fifty-nine thousand, four hundred thirty-four".